Earth drilling bit



Jan. 31, 1933. g 1,895,526

EARTH DRILLING BIT Filed Aug 21, 1951 ia a Altarneys Patented Jan. 31, 1933 UNETED STATES FATE EARTH DRILLING BIT Application filed August 21, 1931. Serial No. 558,446.

My invention relates to earth drilling bits, and has particular reference to a bit for earth bores, such as oil wells and the like. 7

In the art of earth boring, particularly in hard strata, it is common practice to employ a bit comprising a stem upon the lowermost end of which are rotatably mounted a plurality of rotary cutters either in the form of cones, bearing teeth, or in the form of discs, the peripheral surfaces of which are provided with cutting teeth. The employment of disc cutters requires the mounting of certain of the cutters on an axis which forms an acute angle with the axis of rotation of the bit stem, while others of the cutters must be mounted upon an axis which forms a different angle with the axis of the bit stem in order that the two sets of cutters may produce a bore in which the periphery of the bore clears the body of the bit.

It is, therefore, an object of my invention to provide a disk bit having a plurality of cutters arranged in pairs, each pair including a cutter operable upon an axis which extends at an acute angle to the axis of the other outter of the pair and in which a large trunnion forming the axis of one of the cutters has a second trunnion formed thereon for the other of said cutters, permitting the assembly of said cutters one within the other.

Another object of the invention is to provide a disc bit structure wherein a cutter of one set and a cutter of the other set, as described, may be mounted one within the other.

Another object of the invention is to provide a bit structure in which the trunnions or bearings for mounting one of each of the two sets of cutters are formed one within the other.

Other objects of my invention will be apparent from a study of the following specifi cation, read in connection with the accompanying drawing wherein Fig. 1 is a side elevational view, partly in section, of a bit constructed in accordance with my invention, the particular embodiment illustrated being that of a core bit; and

Fig. 2 is another side elevational view, looking in the direction of the arrows II-II of Fig. 1.

Referring to the drawing, I have illustrated a bit structure constructed in accordance with my invention as adapted for employment upon a core bit, such as is employed for earth boring, to permit the removal of a central core from the bore for the purpose of studying the strata formation through which the bore extends.

The bit structure shown is illustrated as comprising a bit head 1 constructed of a substantially tubular piece of metal, the upper end of which is provided with an upwardly extending tapered head 2 having threads 3 for permitting the same to be engaged by the connector upon the end of a drill string, not shown. The lower'end of the bit head 1 is illustrated as being provided with an annular recess 4, the outer surface of which is threaded as at 5 to receive a disc supporting member 6 and to hold the same in assembled relation upon the bit head 1.

At equally spaced intervals around the outer periphery of the disc supporting memher, I provide a plurality of outwardly extending trunnions, two of which are shown in the embodiment of my invention illustrated herein, as designated by'the reference characters 7 and 8, these trunnions being formed upon diametrically opposite sides of the disc supporting member 6.

The trunnion 7 is illustrated as having its axis 9 extending outwardly and downwardly relative to the major axis of rotation of the bit head 1. This trunnion may be formed in any suitable manner, though I prefer to cut away a portion of the outer periphery of the supporting member 6 to form a circular boss having the axis 9. The trunnion or boss 7 constitutes the bearing upon which an inner cutter 10 may rotate, the cutter 10 being preferably spaced from the surface of the trunnion 7 as by means of a suitable wear bushing 11 and a wear washer 12. As illustrated, the cutter 10 comprises a disc of metal of suitable characteristics to provide a hard cutting material upon the outer periphery of which is formed a plurality of V-shaped teeth 13. The cross sectional configuration of the disc 10 is preferably that of a portion of a cone, the base of which is directed toward the supporting member 6, while annular recesses 1 1 and 15 may be formed upon the inner periphery of the discs to constitute shoulders engaging the wear ring 12 and the 5 wear bushing 11.

The disc 10, when rotated by rotation of the bit head 1, will cut an annular groove in the earth, this groove having a width equal to the thickness of the cutter 10. However,

the outer periphery of such annular bore will not permit progress of the cutter into the bore since the outer periphery of such bore is smaller than the path through which the out ermost portion of the cutter 10 moves. For

this reason a second cutting disc 16 is provided and is mounted upon a bearing pin or trunnion 17 which may be formed by machining a recess 18 radially into the outer end of the boss or trunnion 7 As illustrated, the axis 19 of the pin 17 extends radially toward the axis of rotation of the bit head 1 but forms a considerable angle with the axis 9 of the trunnion 7 so that the cutter 16, when rotating upon the pin 19, will have its outermost edge 20 extending considerably beyond the outer periphery of the path of movement of the outermost portion of the cutter 10. Thus the angular bore which is cut by the cutter 16 will provide a clearance for the entire bit head support and cutter assembly.

A wear bushing 21 is preferably interposed between the inner periphery of the cutter 16 and the trunnion or pin 17, a suitable radial flange 22 being formed upon the outer end of the bushing 21 to engage a radial shoulder 23 formed by a. recess in the outer side of the cutter 16.

The assembly of the cutters 10 and 16 upon their respective trunnions is as follows: First the wear ring 12 is placed upon the trunnion 7, after which the bushing 11, assembled within the cutter 10, is then placed upon the trunnion 7. N xt the cutter 16, assembled with its bushing 21, is placed over the pin 17 and the entire assembly held in place by means of a retaining plate 241 having a substantially wedge shaped cross section to provide a narrower portion immediately in 0 front of the pin 1'7, while the upper, inner side of the retaining plate 2 1 may be cut away to align with the outer surface of the bushing 11. Thus by securing the retaining plate 2 1 to the pin 17, as by means of screws 25, the entire assembly of cutters and bushings may be held in place.

lVhile the support 6, trunnions 7 and 17, and cutters 10 and 16, may be employed for ordinary drilling of a bore, my construction is particularly adapted for use as a core bit by providing a central bore 26 extending axially through the support 6, the upper end of which may be threaded as at 27 to receive a core guide 28 into which may pass the central core left by the annular cuts made by the disc cutters. If desired, a suitable core catcher may be provided comprising an annular ring 29 having attached thereto a plurality of resilient core catching fingers 3O distributed around the ring for the purpose of engaging the core and lifting the same when the bit structure is elevated out of the bore. The ring 29 may be retained in a suitable recess 31 cut into the inner periphery of the support 6. Slush lubrication for the cut ters 10 and 16 is suitably provided by providing circulating bores 32 extending into communication with the recess 18 and communicating at their upper ends with the interior of the bit head 1, such communication being indicated at 83 so that drilling fluid which may pass downwardly through the drill stem will pass directly into contact with and wash the cutter 16 and thence be distributed by the cutter to the bottom of the bore so that both the cutter 16 and the cutter 10 will be lubricated.

It will, therefore, be observed that I have provided an earth boring bit which embodies the principle of disc cutters, but which, by reason of the trunnion assembly described herein, permits a very compact arrangement of the parts.

WVhile I have illustrated and described the preferred embodiment of my invention, I do not desire to be limited to any of the details shown or described herein, except as defined in the appended claims.

I claim:

1. In an earth drilling bit, two sets of substantially disc-like cutters, a support for said cutters having means to attach the same to a drill string, means on said support for rotatably mounting said cutters, including a trunnion for mounting a cutter of one of said sets formed on said support with the axis thereof forming an acute angle'to the axis of rotation of said drill string, and'a second trunnion for mounting a cutter of the other set formed on said first trunnion with its axis extending at a difierent angle with respect to the axis of rotation of said drill string.

2. In an earth drilling bit, two sets of substantially disc-like cutters, a support for said cutters having means to attach the same to a drill string, means on said support for rotatably mounting said cutters, including a trunnion for mounting a cutter of one of said sets formed on said support, a second trunnion for mounting a cutter of the other set formed on said first trunnion, the axes of'both of said trunnions lying in the same vertical plane and extending at an acute angle relative to each other.

3. In an earth drilling bit, a cutter support having means thereon to attach the same to a drill string, a trunnion formed on said support extending outwardly and downwardly relative to the axis of rotation of said drill string, a recess formed in the outer surface of said trunnion and a second trunnion extending outwardly and upwardly relative to said axis, formed integrally with said first named trunnion, and a pair of disc-like cutters one mounted for rotation upon said first named trunnion and the other mounted in said recess for rotation upon said second named trunnion.

l. In an earth drilling bit, a cutter support having means thereon for attaching the same to a drill string, a plurality of trunnions formed upon said cutter support at equally spaced intervals around the axis of rotation of said drill string, the axis of each of said trunnions extending at an acute angle to the axis of rotation of said drill string, a substantially disc-like cutter mounted on each of said trunnions, a second trunnion formed upon and integrally with each of said first named trunnions, the axis of the last named trunnion forming an acute angle with the axis of its associated trunnion, and a second disc-like cutter mounted for rotation on each of said last named trunnions.

5. In an earth drilling bit, a cylindrical cutter support having means formed upon one end thereof to attach the same to a drill string, a trunnion formed upon and integrally with the outer wall of said cylindrical support, the axis of said trunnion extending outwardly and downwardly relative to the axis of said drill string, a second trunnion formed integrally with said first trunnion, the axis of which extends outwardly and upwardly relative to the axis of rotation of said drill string, and a substantially disc-like cutter mounted upon each of said trunnions.

6. In an earth drilling bit, a cylindrical cutter support having means formed upon one end thereof to attach the same to a drill string, a trunnion formed upon and integrally with the outer wall of said cylindrical support, the axis of said trunnion extending outwardly and downwardly relative to the axis of said drill string, a second trunnion formed integrally with said first trunnion, the axis of which extends outwardly and upwardly relative to the axis of rotation of said drill string, the axes of both of said trunnions lying in the same vertical plane, and a substantially disc-like cutter mounted upon each of said trunnions.

7. In an earth drilling bit, a cylindrical cutter support having means formed upon one end thereof to attach the same to a drill string, a trunnion formed upon and integrally with the outer wall of said cylinder support, the axis of said trunnion extending outwardly and downwardly relative to the axis of said drill string, a second trunnion formed integrally with said first trunnion, the axis of which extends outwardly and upwardly relative to the axis of rotation of said drill string, a bushing on said first named trunnion, a disc-like cutter mounted upon said bushing, a second bushing upon said second named trunnion abutting said first named bushing, and a second disc cutter mounted for rotation upon said second bushing.

8. In an earth drilling bit, a cylindrical cutter support having formed upon one end thereof means for attaching the same to a drill string, a trunnion formed upon the outer Wall of said cylindrical support, the axis of said trunnion extending outwardly and downwardly relative to the axis of rotation of said drill string, a cutter rotatable on said trunnion an arcuate recess formed within the outer end of said trunnion, a second trunnion formed upon said first trunnion and extending into said recess, the axis of said last named trunnion forming an acute angle to the axis of said first named trunnion, and a disc-like cutter mounted for rotation upon said second named trunnion and operating in said recess.

9. In an earth drilling bit, a cylindrical cutter support having formed upon one end thereof means for attaching the same to a drill string, a trunnion formed upon the outer Wall of said cylindrical support, the axis of said trunnion extending outwardly and downwardly relative to the axis of rotation of said drill string, a cutter rotatable on said trunnion an arcuate recess formed with in the outer end of said trunnion, a second trimnion formed upon said first trunnion and extending into said recess, the axis of said last named trunnion forming an acute angle to the axis of said first named trunnion, a disclike cutter mounted for rotation upon said second named trunnion and operating in said recess, and means mounted upon said second named trunnion for retaining both of said cutters upon their respective trunnions.

Signed at Los Angeles, California, this 29th day of July, 1931.

CONRAD R SOLUM. 

